In communications networks, such as multimedia home networks that make use of broadband powerline communication (PLC), it may be advantageous under certain circumstances to change the level of power at which digital data is communicated between and amongst network nodes. The injected power spectral density (PSD) of a signal in a PLC communications channel may be reduced below a nominal or maximum injected PSD for the channel to conserve power or to comply with regulations for conducted or radiated emissions in a particular frequency band. Alternatively, for example, the injected PSD may be reduced in one or more of the highest powered sub-bands of a plurality of sub-bands in a communications channel to effect an overall improvement in the Signal to Noise Ratio (SNR) for the communications channel. Determining when and how to do these things has not heretofore been addressed.